220-240V uC controlled switch

Discussion in 'General Electronics Chat' started by falcon74, Aug 27, 2010.

  1. falcon74

    Thread Starter New Member

    Jun 6, 2010

    Pardon the noobish tone and language in this question. My electronics background is hobby oriented, without formal education.

    Could someone share some pointers or slight guidance (on direction to look). I would like to be able to control the power-supply to some inductive load s.a. 1000W, 1HP pump (on a 15Amp, 230V 50Hz domestic power-line) and some lighter resistive load s.a. an incandescent lamp @60W, 230V 50Hz, on 5Amp domestic power-line, under the control of a microcontroller.

    The loads are generally in "OFF" state, but need to be kept on for certain duration, e.g. pump for about 30mins at a stretch and incandescent lamp for about 4 hours.

    I understand the uC part, but not clear on how to switch (on/off) the high current lines. I believe I could use Relays (any specific kind?) and something called Solid-State Relay with OptoIsolator. Is this the correct approach ? Also, I would prefer to use the same uC pin to switch on/off multiple such loads. For example at time T0 switch ON pump-1, at T0+1sec switch ON pump-2, at T0+2sec switch ON lamp-1... and then at T0+1800sec (30min) switch OFF pump-1, at T0+1801sec switch OFF pump-2 and so on.

    One of the constraints is to keep the project cost as low as possible, but not compromise on reliability or predictability of the switch to work.

    Last edited: Aug 27, 2010
  2. tom66

    Senior Member

    May 9, 2009
    Use a 250V (contact voltage, *not* coil voltage) relay rated at 5A. This will allow you to control 1kW loads, and the relay doesn't care about the type of load (inductive, resistive, etc.)